For many years the paper used in computer printer machines ("printers") has been manufactured in long lengths to allow continuous feed to the printer. Each length has horizontal lines of perforations at 11 inch intervals to allow paper that has been run through the printer to be torn and removed from the printer. The horizontal perforations also allow the paper to be folded into cartons which hold the paper until fed into the printer. In present practice, each length of paper between adjacent horizontal lines of perforation counts as one sheet, and one carton of paper usually contains between 750 and 3500 sheets. The paper also has a vertical line of perforation running along each edge of the paper, usually at a one-half inch distance from each edge, to allow the removal of the one-half inch margins which contain feeder holes. The feeder holes, which usually number two per inch, serve only the purpose of allowing the paper to be pulled through the printer by feeder pins on tractor wheels. These feeder holes are not considered to be lines of perforation for purposes of this application.
In the prior art, only one size of sheet can be produced from any one length or carton of computer paper. Three of the most common sizes of sheet are: (1) 91/2.times.11 inches, (2) 91/2.times.14 and (3) 147/8.times.11 inches. Upon removal of the feeder hole margins, each of the above sheet sizes produces, respectively: (1) an 81/2.times.11 inch letter size page, (2) an 81/2.times.14 inch legal size page, and (3) a 137/8.times.11 inch spreadsheet page. However, no one length or carton of paper can produce all three sizes of sheets or pages. Consequently, any change in the page size requires that the paper currently in the printer be physically detached and that the paper producing the desired page size be physically inserted into the printer.
Also in the prior art, the tractor wheels on the printer is often positioned approximately 2.75 inches above the tear bar. In order to remove a sheet from the printer, the bottom line of perforation of the printed sheet must be positioned above the tractor wheel. As a consequence, the top edge of the next sheet (the "first blank sheet") is 2.75 inches beyond the tear bar and thus beyond the line on which printing would begin on the first blank sheet. Since the operator generally prefers that printing begin at the top of a sheet rather than 2.75 inches down from the top, he must advance the paper until the bottom of the first blank sheet is just above the tear bar and the printhead is at the top of the following blank sheet. The first blank sheet is torn off when the bottom of that sheet has advanced to the tractor wheels. This results in the wastage of the entire length of the first blank sheet, or 11 to 14 inches of paper.